Those who spend time living out-of-doors, whether for pleasure or as part of a gainful occupation, and particularly those who traverse sparsely inhabited regions, have long recognized the value of having shelter available at night or in inclement weather. Thus, many forms of tents have been devised in varying degrees of complexity. Many tents available today make effective use of modern materials, including plastics, light-weight and water-repellent fabrics, which may also be all or part plastic, and light-weight metals.
The camper or outdoor traveler who is traversing back country on foot often becomes aware of another need, that for a watercraft of some type to help him or her cross a lake or stream which blocks the desired path. Most often, it is necessary to walk a considerable distance to find a way around a lake or to find a place where a stream can be crossed without swimming. Since someone living in remote areas usually relies on fish as a significant part of his or her diet, it is also important to have a fishing craft available. While inflatable mattresses are commonly available, and can double as a raft in emergency circumstances, they are recognized as being somewhat more useful to sleep on than as practical devices for water transportation or fishing because they are not sufficiently rigid. Those which are adequately rigid to hold an adult person above the water are so heavy and require such pressure for proper inflation that they cannot readily be orally inflated and are difficult to transport in a backpack fashion along with the other necessary equipment.